A dense ZrB2-SiC-Si/SiC-Si coating to protect carbon/carbon composites against oxidation at 1773 K and 1973 K

A dense double layer ZrB2-SiC-Si/SiC-Si coating with high content of ZrB2 was designed and fabricated by dipping-carbonization joint gaseous silicon infiltration. This coating can protect C/C substrate from oxidation in air at 1773 K for 500 h with a weight gain of 1.14 %. Such good oxidation protective performance was ascribed to the dense compound silicate oxide layer accompanied by ZrSiO4/ZrO2 pinning phases and compressive stress field around ZrB2 particles during oxidation. Besides, introducing abundant ZrB2 phase could inhibit the evaporation of silicate glass at 1973 K, which could protect C/C composites for 78 h with a weight loss of 1.16 %.

Automated summary

The dense double layer ZrB2-SiC-Si/SiC-Si coating effectively protects the C/C substrate from oxidation, attributed to the high content of ZrB2 and the mechanism of inhibiting the evaporation of silicate glass.